Abstract : The book presents questions on the theory of digital integrators which are main units of digital integrating machine. General methods of analysis of the process of numerical integration in digital integrators are considered. Obtained results are based on synthesis of algorithms of digital integrating, differentiating, factoring, dividing, and summing units, operating with incremental flows. Errors of digital integrators are investigated. Topics included are: Digital-analog computers; Numerical methods of integration in digital integrators; Quantization of quantities in digital integrators and delta transformation of continuous functions; Algorithms digital integrators; Serial and parallel digital integrators; Encoding of numbers and increments in digital integrators; Mathematical operation with flows of increments; Functional diagrams of digital integrators; Errors of digital integrators.